• Principal accomplice
• Principal amount
• Principal bassoonist
• Principal cellist
• Principal clarinetist
• Principal concern
• Principal dancer
• Principal danseuse
• Principal declarant
• Principal devisee
• Principal earner
• Principal eigenvector
• Principal expositor
• Principal flautist
• Principal focus
• Principal furnisher
• Principal investigator
• Principal legatee
• Principal objective
• Principal objector